Kantarou's features are stark opposite of Haruka's. His short, slightly wavy, hair is a light, silver-grey (almost white), while his large eyes are red. He has a pale complexion due to him being an albino. Despite being an adult, his soft features make him seem more like a young boy than a man.

As a person his ability and appearance have affected his way of living from the time he was very young. It ostracized him from other people, thus making him uncomfortable around large crowds. He can lack confidence and be self-concious at times. When he was a child, he spent most of his time around youkai, (his abilities to see them allowing him to do so) and considers himself good at making friends with them. Because he was with the youkai for the majority of his childhood, he never really stayed around humans and has not really developed good people skills.

Despite this, he is a very good manipulator, able to fool others into doing what he wants. He is highly intelligent and extremely sneaky. When interacting with others though, he will adopt a more serious and business-like nature. Either they are contacting him to deal with an issue as an exorcist, his editor Reiko is urging him to finish his latest manuscript, or he is trying to sell something to someone. He has been described as a 'tactician' by Haruka due to how he organizes his plans, thinks ahead and how he manipulats a situation to one that suits him.

It has been known that Kantarou was a loner when he was a child, and suffered from an isolated childhood. He was also bullied by other children because they thought him as strange (because of his ability to see youkai). His mother never cared for him, and the strong resentment he feels for her have governed him for most of his life. For the majority of his childhood, he spent his time around youkai, thinking that they were his only friends.

Kantarou has very deep feelings for Haruka. He admires him greatly because of his strength and power. Despite his admiration, he tends to force Haruka into doing chores for him and protecting him. The name "Haruka" was the name he planned to give him ever since he was a child. He had strived since he was told about him to meet him and befriend him.

Kantarou is the master of Youko. He treats her like a servant, tricking her into doing his work countless times, but he genuinely cares for her. His feelings showed greatly, through depression, when Youko attempted to leave; saying he wasn't hungry. As soon as he learned that she was safe, his appetite returned.

Reiko is his publisher. Their relationship is mostly business-related, though he has made Haruka go out of his way to make sure she is safe. Reiko is the only person who can really manipulate Kantarou; he seems afraid of her at times.